Today, very few homes are without an audio and/or a video component system comprised of several electronic components. Such components possess input and output receptacles for wiring the components together into an audio and/or video system. These input and output receptacles are standardized to allow maximum compatibility among and between the video and/or audio components. Also, electronic test equipment contains the same standardized input and output receptacles for ease of testing and to allow compatibility with other test equipment. These receptacles are most often hollow, cylindrical recesses. They receive a male electrical connector commonly known as a banana plug.
There are currently two common types of banana plugs available. The first is a cylindrical piece of metal with two intersecting cuts passing through the entire length of the banana plug tip. While simple and relatively inexpensive to manufacture, the first type of banana plug suffers from a disadvantage. This type of connector provides electrical contact only at the end of the tip because of the uniform tip diameter and the limited spring action of the design.
Efforts to increase the area of electrical contact between male and female connectors led to a second design for banana connectors. This design features a metal tip covered by a second piece of metal. The thin second piece of metal is cut in the shape of a cross. The center of the cross is placed over the end of the connector tip and the arms of the cross are bent down along the length of the tip. The resulting connector budges slightly at the midpoint, providing some spring action and increased electrical contact area. This design also has several disadvantages. The additional steps of covering the connector shaft with a second piece of metal increases manufacturing costs. Also, unless a relatively expensive alloy such as berylium copper or phosphor bronze is used, the thin second piece of metal eventually becomes fatigued and loses its spring action, thereby reducing the reliability of the electrical contact.